Roller skates typically include multiple wheels attached to a sole portion of a skate shoe. Conventional four wheel roller skates have a pair of front rollers sharing one axis of rotation and a pair of rear rollers sharing a second axis of rotation that is parallel to the axis of rotation of the front rollers. Since each roller is transversely displaced from the longitudinal center line of the roller skate, the conventional roller skate inherently provides substantial lateral stability.
In contrast, in-line roller skates typically have multiple wheels arranged in longitudinal alignment along the longitudinal center line of the skate. Each wheel has a unique axis of rotation that is parallel to the axes of rotation of the other wheels. None of the wheels are transversely displaced from the longitudinal center line of the skate. Accordingly, the in-line skate provides less lateral stability than four wheel roller skates.
Providing a skate that has the ability to switch from a conventional four wheel roller skate configuration to an in-line roller skate configuration is desirable for a number of reasons. First, in-line skating is a natural progression from (and more difficult than) conventional four wheel roller skating. Accordingly, for training purposes, a skate that can be converted from a conventional roller skate to an in-line skate facilitates a user's learning of in-line skating while saving the user the cost of purchasing two different types of skates. Second, convertible skates provide increased comfort and security. For example, an average in-line skater faced with a difficult bit of terrain can simply convert the skate from the in-line configuration to the conventional four wheel roller skate configuration to traverse the terrain. Finally, convertible skates are especially appropriate for use by children or other beginning skaters. Convertible skates provide both the training advantages and the comfort and security features that are desired when the skate is used by a child or beginner. In particular, a convertible skate allows a child or beginner initially to learn conventional four wheel roller skating while providing the opportunity to advance to in-line skating if the child or beginner desires. In addition, depending on the type of terrain on which a child will be skating, a parent can determine whether the child should skate in the conventional four wheel roller skating configuration or the in-line skating configuration.
Several convertible skates have been proposed that provide the ability to switch from a plural wheel roller skate configuration to an in-line skate configuration. U.S. Pat. No. 5,524,911 to Cochimin discloses a convertible skate that can be changed from a conventional four wheel skate to an in-line skate configuration. The Cochimin device has two chassis, each of which has two wheels and is rotatable about a post on the bottom sole of the skate. Each wheel is linked by a tie rod to a collar located on the central post. Accordingly, conversion of the skate from a conventional four wheel roller skate to an in-line skate is accomplished by unscrewing a bolt located on the central post to loosen the chassis, and then turning the chassis 90.degree.. The tie rods that are connected between the wheel support and the collar on the central post cause the wheels to turn with respect to the chassis. Accordingly, the wheels' axes of rotation remain perpendicular to the longitudinal axis of the skate when the chassis is turned 90.degree. and into the inline configuration.
Although the Cochimin skate achieves conversion from a conventional roller skate configuration to an in-line skate configuration, the structure necessary to achieve this function is complicated, difficult to operate, and does not adequately lock the axis of rotation of the wheels perpendicular to the longitudinal axis of the skate.
U.S. Pat. No. 5,372,534 to Levy et al. discloses a "variable geometry wheeled conveyance" type of toy vehicle in which two pairs of wheels located at the base of the toy vehicle can be automatically moved from a first configuration to a second configuration. A parallelogram linkage connected to a motor coordinates the movement of the two pairs of wheels in much the same way that the wheels of the Cochimin device are caused to move. In particular, a rack and pinion system rotates two cross links through an angle of 90.degree. to cause wheels located thereon to move from the first configuration to the second configuration. The axes of the wheels located on the cross links remain perpendicular to the longitudinal axis of the conveyance due to their connection to two "tie rods" of the parallelogram linkage. Although the preferred embodiment of the Levy device is a toy vehicle, Levy indicates that the mechanism could be applied to a roller skate. A roller skate that includes the varied geometry wheel disclosed in the Levy patent will inherently include the drawbacks noted above with regard to the Cochimin device because the basic moving linkage and wheel motion of the Levy device is similar to that of Cochimin.
U.S. Pat. No. 5, 449,183 to Klamer et al. discloses an integral multi-function roller skate system that can be converted from an in-line skate to a multi-axis dual wheel conventional skate. As disclosed in the patent, six wheels can be joined together in pairs by a rack and pinion system so that each pair of wheels forms a single larger wheel. Accordingly, the skate is convertible from a conventional multiple wheel roller skate to an in-line skate. However, this design does not provide the same skating characteristics as an in-line skate because pairs of wheels are placed adjacent each other in the in-line skate configuration. Each pair of wheels effectively forms one wide wheel, which does not produce the same skating characteristics as a narrower wheel.
Another desirable feature of an in-line skate adapted for use by children or inexperienced adults is a reverse spinning brake device. By limiting the rotation of one or more wheels to one rotational direction (corresponding to forward movement of the skate), a user can generate propulsion by pushing straight back on the skate. Such a reverse spinning brake lock mechanism allows the user to skate up a sloping travel surface without fear of rolling backwards down the slope.
Many different types of brake locks have been used with conventional roller skates. U.S. Pat. No. 4,932,676 to Klamer discloses a conventional roller skate brake lock design that is configurable between a free wheeling, forward only, or full stop configuration. Each roller skate wheel has gear-like teeth located on an inside cylindrical surface of the wheel. A camming member positions a pawl to selectively engage the gear-like teeth of the wheel and therefore control the movement of the wheel. The pawl extends across the body of the skate to engage a pair of wheels, and the camming member engages the pawl intermediate the wheels. This design is not well suited for use in an in-line skate.
Recently, attempts have been made to implement reverse spinning brake locks on in-line skates. One example of an in-line skate that includes a reverse spinning brake lock is disclosed in U.S. Pat. No. 5,620,190 to Maggiore. The reverse spinning brake lock is described as a movement limiting mechanism and is built into the front roller of the skate. The roller includes ratchet teeth located on an inner circumference of the wheel. The ratchet teeth lock with a tongue to selectively prevent rotation of the wheel. The motion limiting device operates in three modes, including a free wheel mode, a forward only mode, and a full stop mode. Selection between the different modes is accomplished by moving a pawl adjuster into three different positions. In a first position, the pawl adjuster locks the tongue in a location central to the axis of the wheel so that no contact between the wheel and the tongue occurs. In the second position, the pawl adjuster allows the pawl to move vertically. Accordingly, the teeth on the inner surface of the wheel push the pawl vertically away during forward rotation and lock with the pawl when the wheel attempts to spin in a rearward direction, thereby preventing rearward rotation. In a third position, the pawl adjuster locks the pawl in a lowered position with the pawl in permanent engagement with the teeth of the wheel. Accordingly, the wheel is locked and prevented from any forward or rearward movement.
Another in-line skate device that incorporates a reverse spinning brake is sold by Playskool, Inc. of Pawtucket, Rhode Island. The Playskool reverse spinning brake includes a knurled rod located immediately behind the front wheel of the in-line skate. When the front wheel spins in a reverse direction, the knurled rod wedges into a space between the front wheel and a wall that angles down towards the front wheel. The knurled rod effectively brakes the front wheel in the reverse direction. When the front wheel spins in a forward direction, the knurled rod is urged upwards into the opening provided by the angled wall. When the reverse spinning brake feature is not desired, a switch located at the side of the skate moves a lever to lift and lock the knurled rod into the opening provided by the angled wall.
The movement limiting devices discussed above would not accommodate moveable wheels.